[EM] VoteFair popularity ranking Scored: Steve's dialogue with Richard Fobes

[steve bosworth]

> Date: Thu, 17 Sep 2015 11:44:23 -0700
> From: ElectionMethods at VoteFair.org
> To: election-methods at electorama.com
> CC: stevebosworth at hotmail.com
> Subject: Re: A Question about Pages 22-29/58 of Chapter 12 of Fobes' 'Ending the Hidden Unfairness of U.S. Elections
  Hi Richard ( and everyone else), Later I want to continue our dialogue compare VoteFair and APR for electing multiple winners, but now, please let me focus only on your explanation below about 'VoteFair popularity scoring' for electing single-winners and the need not to rely on shortcuts: S:  As you may recall, I currently favor your VoteFair popularity ranking method for electing single-winners -- presidents, governors, majors, etc.  It has the virtue of discovering the most popular candidate by counting all the preferences of all the voters and without eliminating any candidate until the most popular one has been discovered.  It seems simpler and better than any other method that I have read about, including those I've seen discussed in EM.  Still, I would like to receive any criticisms from anyone of this method for this purpose, or any arguments that prefer a competing method. Richard, I think your method would be even more appealing if it were safe to score its results by the 'shortcut' I asked about.  It would be more appealing because more people would be able to understand exactly how it works, as well as it requiring a much simpler computer program. I understand that 'shortcuts' in general can be dangerous and that the particular ones you mention below with regard to 'plurality' and 'IRV' are flawed by the reason you give, i.e. their mistaken assumptions which motivate them.    However, I am not yet aware that VoteFair popularity ranking makes any mistaken assumptions.  Therefore, it currently still seems to me that simply counting the number of times each candidate is preferred over every other candidate would not be an unreliable 'shortcut' because would always enable us to discover the most popular candidate, as well as give use the whole correct sequence.  Is there specific reason why I am mistaken in this view?Steve > 
> On 9/13/2015 12:22 PM, steve bosworth wrote:
>  > ...
>  > [...] please [...] explain why the following simpler set of
>  > calculations would not also always allow us to discover the most
>  > popular sequence:
>  >
>  > Firstly, find the grand total of preferences given by the 100 voters to
>  > each of all the candidates (4 in this example) over each of the other
>  > candidates (3 in this example). The result is:
>  > Elliot 200
>  > Selden 180
>  > Meredith 90
>  > Roland 80
>  >
>  > At least in this case, the same sequence is produced:
>  > Elliot 1st, Selden 2nd, Meredith 3rd, and Roland 4th.
> 
> Yes, sometimes -- in SOME situations -- a simpler calculation (such as 
> this one) can identify the same winner and even the same ranking.
> 
> However, typically a shortcut fails to provide fair results in ALL 
> situations.
> 
> Consider that plurality (first-past-the-post) voting is a shortcut that 
> mistakenly assumes that the candidate with the most first-choice votes 
> is always the most popular.  This shortcut does not work if the 
> candidate with the most first-choice votes does not ALSO get a majority 
> of (more than half) the votes.
> 
> In a similar way, instant-runoff voting is a shortcut that does work in 
> some situations.  It is based on the shortcut of (mistakenly) assuming 
> that the candidate with the fewest first-choice votes is least popular.
> 
> Also in a similar way, your APR method will work in some situations. 
> Yet it too puts too much emphasis on first-choice votes without 
> considering secondary preferences (or somewhat-equal preferences for 
> those who prefer approval voting).
> 
> In contrast to methods that work SOME of the time, full fairness 
> requires that a method must produce fair results either ALL the time 
> (which is mathematically impossible if all fairness criteria are 
> considered), or MOST of the time.  In the best methods, unfairness 
> (according to any fairness criteria) is rare.  To get this level of 
> fairness, the voting method must look beyond the first-choice counts.
> 
> Back before computers became available, mathematical shortcuts were 
> often useful in some situations.  Now, both in terms of calculation time 
> and the work of coding software, it's easier to do full calculations 
> using a fully-fair algorithm, compared to writing code that handles both 
> the shortcut and all the needed validity checking and related decision 
> handling (to handle the cases where the validity checks fail).
> 
> I hope this information helps not only you/Steve, but also helps some 
> other participants in this forum.
> 
> Richard Fobes
> 
> BTW, page numbers in an ebook reader do not match the page numbers in a 
> different ebook reader, and do not match the page numbers in a printed 
> edition.
> 
  		 	   		  
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